The purpose of this study is to investigate whether diagnostic bronchoscopy can be safely and potentially more effectively performed without the use of tracheal intubation or a supraglottic airway, under completely unobstructed surgical conditions afforded by THRIVE: Transnasal Humidified Rapid- Insufflation Ventilatory Exchange. THRIVE provides patient's gas exchange through rapid insufflation of high-flow oxygen via specialized nasal cannula.